91 results about "Color constancy" patented technology

The invention discloses a color digital image enhancing and denoising method under random illumination. The method is characterized by comprising the following steps of: 1, image denoising processing, namely converting an original image from an RGB space to a YCbCr space, removing a Gaussian noise by using a Gaussian filter and removing a salt and pepper noise by performing median filter; 2, image brightness/contract stretch processing, converting the image from the RGB space to an HSI space, decomposing the image by using a two-sided filter, processing by an improved Retinex model algorithm, and obtaining a new image saturation by performing saturation compensation; and 3, performing fusion display on the image acquired after denoising the YCbCr space and the image acquired by HSI space processing. By the method, the color constancy of the image can be kept, the dynamic range of the image can be improved well, and simultaneously noises of the image can be inhibited and removed with less texture and detail information loss.

The invention relates to a color constancy calculating method and a system based on a derivative structure of an image, belonging to the technical field of color constancy calculation and image light treatment. The color constancy calculating method comprises the steps: firstly, extracting image features based on the derivative structure of the image, providing a feature vector of a chromaticity histogram, so as to be used for calculating the color constancy; secondly, training the feature vector of the chromaticity histogram by applying an ELM neural network, using the illumination chromaticity corresponding to every training image to constitute an output vector of the neural network; and finally, carrying out illumination correction to the tested image by an opposite angle model, so as to obtain image color under white light. The invention fully utilizes the feature information of the derivative structure of the image to improve the calculation performance of the color constancy, and has the advantages of high learning speed, strong generalization capability, and capability of simultaneously carrying out the evaluation of two-dimensional illumination chromaticity, and the like.

The invention is directed to a photosensor for color measurement based on three spectral components, particularly for highly accurate color measurement for testing and guaranteeing color constancy in engineered surfaces and consumer articles of any kind. The object of the invention, to find a novel possibility for color measurement based on a three-range method with color measurement values generated by preceding interference filters with different spectral responses which permits a virtually true-color measurement in conformity with standards in a simple manner without costly reference light calibration, is met according to the invention in that the photosensor comprises at least three partial surfaces which are covered by different interference filters adapted to the X-, Y- and Z-spectral characteristic of the human eye, each partial surface being arranged so as to be uniformly distributed in a sector-shaped manner and so as to cover the same area around a center with passivated webs located therebetween, and every partial surface is provided with an interference filter whose transmission characteristic over the wavelength of the light to be measured spectrally is adapted to the response of the human eye, wherein the spectral components passed by the interference filters approximate the normal spectral value functions of the human eye in color coordinates of the color space.

Described herein is the use of a combination of organic additives that is particularly advantageous for the preparation of cementitious compositions having a high conservation of the degree of white, which contain in mass a photocatalyst that is able to oxidize, in the presence of light, air and ambient humidity, pollutant substances present in the environment, the said photocatalyst being, in particular, titanium dioxide prevalently in the form of anatase.The above combination of additives comprises the following: a melamine resin; a cellulose ether; a polymer chosen from among an ethylene polymer, an acrylic polymer, and a terpolymer comprising as co-monomers at least one ester of acrylic acid with an alcohol and at least one ester of vinyl alcohol with a carboxylic acid, or alternatively, an acrylic, styrene or butadiene latex; and a chemically modified starch.

The invention discloses a color constancy method in two steps under complex illumination, belonging to the technical fields of computer vision, image processing and pattern recognition. The invention provides a novel color constancy method in two steps according to principles that a human visual system has independent color passage and bright passage at early stage and visual information processing has modularity. The method comprises the following steps: firstly, utilizing pixels nearby edges to estimate color offset information of an original image, correcting color offset of a color-offset image through white balance; and secondly, according to the color relativity characteristic of three components in an RGB color space, performing same proportion enhancement on the three components of RGB of a color image through obtaining a bright gain curved surface to finally obtain a color image with unchanged color. The method of the invention solves the mal posed problems of traditional color constancy, can preferably maintain the constancy of color under color offset, low luminance and other complex illumination, can effectively improve the contrast and brightness of the image simultaneously and has good universality.

A method for providing partial color constancy of a stimulus represented by an array of picture elements each represented by a color spectrum. The method comprising: (a) assigning to each picture element in the array, for each color, a color value, thereby to provide a plurality of pre-processed single color images each respectively arranged as a series of pre-processed color values one at each picture element; (b) for each picture element, defining at least two regions of picture elements; (c) at each picture element, adapting each one of the pre-processed color values using pre-processed color values from at least one of the two regions of picture elements, thereby to form, at each picture element, a set of center response values; and (d) at each picture element, transforming the set of center response values into a set of center corrected color values, using response values from the two regions of picture elements to provide a plurality of processed single color images having partial color constancy.

The invention relates to a water harness on-line measurement device. A measurement method of the water hardness on-line measurement device based on solution image technology is characterized by adding dropwise EDTA into a quantitative water solution with the pH of 10.0 plus or minus 0.1 by using a constant flow adding pump with chrome black T or acid chrome blue K as indicator, L-cysteine hydrochloride and triethanolaminesolution as screening agent and ethylenediaminetetraacetic disodiumsalt solution as titrant, recording the volume of added EDTA (Ethylene Diamine Tetraacetic Acid) solution by a computer, simultaneously collecting water solution image colors by using a CCD (Charged Coupled Device) image sensor, displaying image color RGB (Red, Green and Blue)-titrating solution volume real-time curve on a computer screen, and calculating the water hardness according to the titrating solution volume corresponding to the inflection point of the RGB-titrating solution volume curve, wherein the detection precision is improved by adopting a color constancy algorithm based on a neutral network to reduce the interference of factors such as a light source, sensor noise and the like. The invention have the choices of high hardness and low hardness on-line measurement, is simple and convenient in operation, and can be used in the industries of electric power, petroleum, chemical industry, metallurgy and the like.

Disclosed is a method for correcting color in a portable image projector in consideration of an effect of a background color when the portable image projector projects images. The method corrects the effect of the background color to be projected, using color constancy technique, and thereby represents high-quality image which can be projected on a white screen. The method includes the steps of determining if a background color exists on a projection screen using a portable camera, converting the size of a mask image in order to connect a spatial position of an original image and an image photographed by a camera, correcting brightness of the mask image in order to correct non-homogeneity of the brightness of the projected image due to the distribution of different brightness values of the background color, and correcting the background color in order to correct color distortion of the image projected in different colors on the background color. The background color correction step includes the sub-steps of initializing chromaticity of the white screen in advance, and correcting chromaticity using a technique of color constancy of human eyesight.

An electronic imaging system operates as closely as possible to the cone spectral response space to obtain a human eye-like long, medium, short (LMS) wavelength response. An input image, for example, red-green-blue (RGB), is transformed to an LMS color space similar to the human long-, middle-, and short-wavelength cone receptor responses. Adaptation levels for each LMS component are calculated. The adaptation levels are then used to adjust the sensitivity of each LMS sensor response to obtain an LMS component image. The LMS component image then is transformed back to an RGB component image for further processing or display.

The invention relates to a color constancy method based on a texture pyramid and regularized local regression, belonging to the technical field of image processing. The color constancy method based on a texture pyramid and regularized local regression comprises the following steps: establishing an algorithm candidate set for the fusion algorithm according to different parameter selections througha Minkowski paradigm based on common color constancy, segmenting an image into overlapped blocks according to different resolution ratios, describing the texture features of each block by adopting Weibull distribution parameters, selecting K images of which the texture features are similar to the texture features of the given images to be measured from a training database according to the definedimage similarity norm, estimating the illumination of the images to be measured by adopting the regularized local regression according to the K reference images in the fusion stage, and finally mapping the images to be measured to the standard white light by using a Von Kries model according to the illumination estimation value to obtain the corrected images. The invention effectively improves the illumination estimation accuracy and can be widely applied to target tracking, object recognition and image retrieval, and the like.

The invention discloses a blocking perception Hash tracking method with shadow removing. The method comprises the steps of: determining shadow areas in an image according to the distribution characteristics of a shadow image in each channel grey-scale map of a CIELAB color space; then utilizing a color constancy theory to recover pixel points in the shadow areas to a non-shadow effect; combining blocking perception Hash coding values with color self-similarity for forming a similarity measure, and carrying out matching on tracked target sub-blocks of adjacent frames based on the similarity measure; and finally, combining the above sub-blocks to obtain the regional position of the tracked target in the current frame, and realizing the tracking of the tracked target in a video. The blocking perception Hash tracking method has the advantages that according to different moving ranges and deforming degrees of human body parts, a human body target is divided into eight sub-blocks, and on this basis, and the blocking perception Hash coding method is provided to solve the problem of an existing tracking algorithm that the tracking is unsuccessful when the human body is partially or totally shielded or partially rotated and when the illumination in the shadow areas and non-shadow areas of a natural scene changes suddenly.

A color constancy method and system include dividing an image into a plurality of sub-images and applying a plurality of color constancy algorithms to each of the sub-images. The outputs of each of the color constancy algorithms are analyzed for each of the sub-images to determine which of the color constancy algorithms give inconsistent results across the sub-images. The influence of the outputs of the algorithms providing inconsistent results is adjusted to decrease their influence (e.g. effect or weight) with respect to the outputs of algorithms providing consistent results. The outputs from the plurality of color constancy algorithms are combined based upon the adjustment of the outputs.

The invention belongs to the technical field of image processing and computer vision, combines an image defogging algorithm and a color constancy algorithm, and proposes a method capable of effectively restoring underwater image visual quality. The technical scheme adopted by the invention is that the underwater image restoration method includes the steps of performing defogging processing on degraded blue and green channels of an underwater image according to an underwater imaging data model, and correcting a degraded red channel on the basis of the restored pixel values of the blue and green channels according to a gray scale world color constancy algorithm. The underwater image restoration method provided by the invention is mainly applied to an image processing occasion.

A system (100), method and computer program product for determining plant diseases. The system includes an interface module (110) configured to receive an image (10) of a plant, the image (10) including a visual representation (11)of at least one plant element (1). A color normalization module (120) is configured to apply a color constancy method to the received image (10) to generate a color-normalized image. An extractor module (130) is configured to extract one or more image portions (11e) from the color-normalized image wherein the extracted image portions (11e) correspond to the at leastone plant element (1). A filtering module (140) configured: to identify one or more clusters (C1 to Cn) by one or more visual features within the extracted image portions (11e) wherein each cluster isassociated with a plant element portion showing characteristics of a plant disease; and to filter one or more candidate regions from the identified one or more clusters (C1 to Cn) according to a predefined threshold, by using a Bayes classifier that models visual feature statistics which are always present on a diseased plant image. A plant disease diagnosis module (150) configured to extract, byusing a statistical inference method, from each candidate region (C4, C5, C6, Cn) one or more visual features to determine for each candidate region one or more probabilities indicating a particulardisease; and to compute a confidence score (CS1) for the particular disease by evaluating all determined probabilities of the candidate regions (C4, C5, C6, Cn).

A system and method are provided for producing a color palette including a multitude of color patterns for a predetermined coloring process with a multitude of defined base colors and for a predetermined substrate. The individual color patterns are systematically, especially equidistantly, defined in a mathematically defined color space by the way of color coordinates describing the color space. The spectrum of the color pattern is synthesized by calculation for each color pattern in the color space by way of a color mixing model representing the predetermined coloring process and the predetermined substrate, whereby that spectrum is selected having the highest color constancy. The spectra synthesized by calculation are stored in relation to the color coordinates of the underlying color patterns. Through use of a mathematical/physical basis (such as the CIE-system), it is possible to define a visually equidistant color space and assign a spectral curve to individual points having the best color constancy.

The present invention relates to a color recovery method and system, and more specifically, to a color recovery method and system that recovers colors of digital images distorted due to lighting by using a principle of implementing color constancy based on a human vision system. The present invention comprises: a) determining criterion region in consideration of variance values for each color channel of images to be recovered; b) computing relative surface reflectance for the determined criterion regions and computing adjustment coefficients for excluding distortion effects of a light source using the computed relative surface reflectance; and c) recovering the colors for the images by using the adjustment coefficient. With the present invention, the distorted colors of digital images due to the spectral bias of a light source can be easily recovered in a very fast single step operation free from the unique color problem, one of the worst problems in the field of color correction technology so-far known as impossible to solve, if and only if there is a sub-region in a digital image containing sufficient number of surface elements of different reflectance.

The invention discloses an image white balance method based on sparse representation. The method comprises the following steps of obtaining a large number of training images under various scenes and environments, utilizing a standard color pallet for conducting measuring to obtain an illumination chromaticity value of each training image in the process of shooting, conducting statistics on the corresponding color feature of each training image, giving a test image, utilizing the illumination chromaticity values and the color features of the training images to estimate the illumination chromaticity value of the test image, utilizing the obtained illumination chromaticity value of the test image, correcting the color of each pixel in the test image through a diagonal model, and obtaining the image after the white balance. The method can be applied to the fields of white balance processing of a camera, illumination transformation of the image, color constancy calculation and the like, and has the wide application prospect.

The invention discloses a method for detecting hard exudation in an eye fundus image based on a multi-light-source color constant model, belongs to the technical field of image processing, and solvesthe problem that the hard exudation detection precision is low due to the fact that a single light source is adopted for color correction in the prior art. The method comprises the following steps: inputting an original fundus image, preprocessing; performing color correction on the preprocessed original fundus image by using a multi-light-source color constancy algorithm; carrying out optic discpositioning by combining the blood vessel information in the fundus image subjected to color correction, and segmenting an optic disc area by utilizing rapid mean shift to obtain an optic disc image;performing threshold segmentation and morphological reconstruction on the basis of the optic disc image and the image obtained by preprocessing, and extracting a hard exuded candidate region to obtaina candidate region image; and extracting color histogram features, color constancy features and texture features of the candidate region image; and using the extracted features for detection to obtain a detection result. The method is used for feature extraction and hard exudation detection of the fundus image.